interface FileSystemInterface

interface FileSystemInterface {
    
    /**
     * Flag for dealing with existing files: Appends number until name is unique.
     */
    const EXISTS_RENAME = 0;
    
    /**
     * Flag for dealing with existing files: Replace the existing file.
     */
    const EXISTS_REPLACE = 1;
    
    /**
     * Flag for dealing with existing files: Do nothing and return FALSE.
     */
    const EXISTS_ERROR = 2;
    
    /**
     * Flag used by ::prepareDirectory() -- create directory if not present.
     */
    const CREATE_DIRECTORY = 1;
    
    /**
     * Flag used by ::prepareDirectory() -- file permissions may be changed.
     */
    const MODIFY_PERMISSIONS = 2;
    
    /**
     * A list of insecure extensions.
     *
     * @see \Drupal\Core\File\FileSystemInterface::INSECURE_EXTENSION_REGEX
     */
    public const INSECURE_EXTENSIONS = [
        'phar',
        'php',
        'pl',
        'py',
        'cgi',
        'asp',
        'js',
        'htaccess',
        'phtml',
    ];
    
    /**
     * The regex pattern used when checking for insecure file types.
     *
     * @see \Drupal\Core\File\FileSystemInterface::INSECURE_EXTENSIONS
     */
    public const INSECURE_EXTENSION_REGEX = '/\\.(phar|php|pl|py|cgi|asp|js|htaccess|phtml)(\\.|$)/i';
    
    /**
     * Moves an uploaded file to a new location.
     *
     * PHP's move_uploaded_file() does not properly support streams if
     * open_basedir is enabled, so this function fills that gap.
     *
     * Compatibility: normal paths and stream wrappers.
     *
     * @param string $filename
     *   The filename of the uploaded file.
     * @param string $uri
     *   A string containing the destination URI of the file.
     *
     * @return bool
     *   TRUE on success, or FALSE on failure.
     *
     * @see move_uploaded_file()
     * @see https://www.drupal.org/node/515192
     * @ingroup php_wrappers
     */
    public function moveUploadedFile($filename, $uri);
    
    /**
     * Sets the permissions on a file or directory.
     *
     * This function will use the file_chmod_directory and
     * file_chmod_file settings for the default modes for directories
     * and uploaded/generated files. By default these will give everyone read
     * access so that users accessing the files with a user account without the
     * webserver group (e.g. via FTP) can read these files, and give group write
     * permissions so webserver group members (e.g. a vhost account) can alter
     * files uploaded and owned by the webserver.
     *
     * PHP's chmod does not support stream wrappers so we use our wrapper
     * implementation which interfaces with chmod() by default. Contrib wrappers
     * may override this behavior in their implementations as needed.
     *
     * @param string $uri
     *   A string containing a URI file, or directory path.
     * @param int $mode
     *   Integer value for the permissions. Consult PHP chmod() documentation for
     *   more information.
     *
     * @return bool
     *   TRUE for success, FALSE in the event of an error.
     *
     * @ingroup php_wrappers
     */
    public function chmod($uri, $mode = NULL);
    
    /**
     * Deletes a file.
     *
     * PHP's unlink() is broken on Windows, as it can fail to remove a file when
     * it has a read-only flag set.
     *
     * @param string $uri
     *   A URI or pathname.
     * @param resource $context
     *   Refer to http://php.net/manual/ref.stream.php
     *
     * @return bool
     *   Boolean TRUE on success, or FALSE on failure.
     *
     * @see unlink()
     * @ingroup php_wrappers
     */
    public function unlink($uri, $context = NULL);
    
    /**
     * Resolves the absolute filepath of a local URI or filepath.
     *
     * The use of this method is discouraged, because it does not work for
     * remote URIs. Except in rare cases, URIs should not be manually resolved.
     *
     * Only use this function if you know that the stream wrapper in the URI uses
     * the local file system, and you need to pass an absolute path to a function
     * that is incompatible with stream URIs.
     *
     * @param string $uri
     *   A stream wrapper URI or a filepath, possibly including one or more
     *   symbolic links.
     *
     * @return string|false
     *   The absolute local filepath (with no symbolic links) or FALSE on failure.
     *
     * @see \Drupal\Core\StreamWrapper\StreamWrapperInterface::realpath()
     * @see http://php.net/manual/function.realpath.php
     * @ingroup php_wrappers
     */
    public function realpath($uri);
    
    /**
     * Gets the name of the directory from a given path.
     *
     * PHP's dirname() does not properly pass streams, so this function fills that
     * gap. It is backwards compatible with normal paths and will use PHP's
     * dirname() as a fallback.
     *
     * Compatibility: normal paths and stream wrappers.
     *
     * @param string $uri
     *   A URI or path.
     *
     * @return string
     *   A string containing the directory name.
     *
     * @see dirname()
     * @see https://www.drupal.org/node/515192
     * @ingroup php_wrappers
     */
    public function dirname($uri);
    
    /**
     * Gets the filename from a given path.
     *
     * PHP's basename() does not properly support streams or filenames beginning
     * with a non-US-ASCII character.
     *
     * @see http://bugs.php.net/bug.php?id=37738
     * @see basename()
     *
     * @ingroup php_wrappers
     */
    public function basename($uri, $suffix = NULL);
    
    /**
     * Creates a directory, optionally creating missing components in the path.
     *
     * When PHP's mkdir() creates a directory, the requested mode is affected by
     * the process's umask. This function overrides the umask and sets the mode
     * explicitly for all directory components created.
     *
     * @param string $uri
     *   A URI or pathname.
     * @param int $mode
     *   Mode given to created directories. Defaults to the directory mode
     *   configured in the Drupal installation. It must have a leading zero.
     * @param bool $recursive
     *   Create directories recursively, defaults to FALSE. Cannot work with a
     *   mode which denies writing or execution to the owner of the process.
     * @param resource $context
     *   Refer to http://php.net/manual/ref.stream.php
     *
     * @return bool
     *   Boolean TRUE on success, or FALSE on failure.
     *
     * @see mkdir()
     * @see https://www.drupal.org/node/515192
     * @ingroup php_wrappers
     *
     * @todo Update with open_basedir compatible recursion logic from
     *   \Drupal\Component\PhpStorage\FileStorage::ensureDirectory().
     */
    public function mkdir($uri, $mode = NULL, $recursive = FALSE, $context = NULL);
    
    /**
     * Removes a directory.
     *
     * PHP's rmdir() is broken on Windows, as it can fail to remove a directory
     * when it has a read-only flag set.
     *
     * @param string $uri
     *   A URI or pathname.
     * @param resource $context
     *   Refer to http://php.net/manual/ref.stream.php
     *
     * @return bool
     *   Boolean TRUE on success, or FALSE on failure.
     *
     * @see rmdir()
     * @ingroup php_wrappers
     */
    public function rmdir($uri, $context = NULL);
    
    /**
     * Creates a file with a unique filename in the specified directory.
     *
     * PHP's tempnam() does not return a URI like we want. This function will
     * return a URI if given a URI, or it will return a filepath if given a
     * filepath.
     *
     * Compatibility: normal paths and stream wrappers.
     *
     * @param string $directory
     *   The directory where the temporary filename will be created.
     * @param string $prefix
     *   The prefix of the generated temporary filename.
     *   Note: Windows uses only the first three characters of prefix.
     *
     * @return string|bool
     *   The new temporary filename, or FALSE on failure.
     *
     * @see tempnam()
     * @see https://www.drupal.org/node/515192
     * @ingroup php_wrappers
     */
    public function tempnam($directory, $prefix);
    
    /**
     * Copies a file to a new location without invoking the file API.
     *
     * This is a powerful function that in many ways performs like an advanced
     * version of copy().
     * - Checks if $source and $destination are valid and readable/writable.
     * - If file already exists in $destination either the call will error out,
     *   replace the file or rename the file based on the $replace parameter.
     * - If the $source and $destination are equal, the behavior depends on the
     *   $replace parameter. FileSystemInterface::EXISTS_REPLACE will replace the
     *   existing file. FileSystemInterface::EXISTS_ERROR will error out.
     *   FileSystemInterface::EXISTS_RENAME will rename the file until the
     *   $destination is unique.
     * - Provides a fallback using realpaths if the move fails using stream
     *   wrappers. This can occur because PHP's copy() function does not properly
     *   support streams if open_basedir is enabled. See
     *   https://bugs.php.net/bug.php?id=60456
     *
     * @param string $source
     *   A string specifying the filepath or URI of the source file.
     * @param string $destination
     *   A URI containing the destination that $source should be copied to. The
     *   URI may be a bare filepath (without a scheme).
     * @param int $replace
     *   Replace behavior when the destination file already exists:
     *   - FileSystemInterface::EXISTS_REPLACE - Replace the existing file.
     *   - FileSystemInterface::EXISTS_RENAME - Append _{incrementing number}
     *     until the filename is unique.
     *   - FileSystemInterface::EXISTS_ERROR - Throw an exception.
     *
     * @return string
     *   The path to the new file.
     *
     * @throws \Drupal\Core\File\Exception\FileException
     *   Implementation may throw FileException or its subtype on failure.
     */
    public function copy($source, $destination, $replace = self::EXISTS_RENAME);
    
    /**
     * Deletes a file without database changes or hook invocations.
     *
     * This function should be used when the file to be deleted does not have an
     * entry recorded in the files table.
     *
     * @param string $path
     *   A string containing a file path or (streamwrapper) URI.
     *
     * @throws \Drupal\Core\File\Exception\FileException
     *   Implementation may throw FileException or its subtype on failure.
     */
    public function delete($path);
    
    /**
     * Deletes all files and directories in the specified filepath recursively.
     *
     * If the specified path is a directory then the function is called
     * recursively to process the contents. Once the contents have been removed
     * the directory is also removed.
     *
     * If the specified path is a file then it will be processed with delete()
     * method.
     *
     * Note that this only deletes visible files with write permission.
     *
     * @param string $path
     *   A string containing either an URI or a file or directory path.
     * @param callable|null $callback
     *   Callback function to run on each file prior to deleting it and on each
     *   directory prior to traversing it. For example, can be used to modify
     *   permissions.
     *
     * @throws \Drupal\Core\File\Exception\FileException
     *   Implementation may throw FileException or its subtype on failure.
     */
    public function deleteRecursive($path, callable $callback = NULL);
    
    /**
     * Moves a file to a new location without database changes or hook invocation.
     *
     * This is a powerful function that in many ways performs like an advanced
     * version of rename().
     * - Checks if $source and $destination are valid and readable/writable.
     * - Checks that $source is not equal to $destination; if they are an error
     *   is reported.
     * - If file already exists in $destination either the call will error out,
     *   replace the file or rename the file based on the $replace parameter.
     * - Works around a PHP bug where rename() does not properly support streams
     *   if safe_mode or open_basedir are enabled.
     *
     * @param string $source
     *   A string specifying the filepath or URI of the source file.
     * @param string $destination
     *   A URI containing the destination that $source should be moved to. The
     *   URI may be a bare filepath (without a scheme) and in that case the
     *   default scheme (public://) will be used.
     * @param int $replace
     *   Replace behavior when the destination file already exists:
     *   - FileSystemInterface::EXISTS_REPLACE - Replace the existing file.
     *   - FileSystemInterface::EXISTS_RENAME - Append _{incrementing number}
     *     until the filename is unique.
     *   - FileSystemInterface::EXISTS_ERROR - Do nothing and return FALSE.
     *
     * @return string
     *   The path to the new file.
     *
     * @throws \Drupal\Core\File\Exception\FileException
     *   Implementation may throw FileException or its subtype on failure.
     *
     * @see https://bugs.php.net/bug.php?id=60456
     */
    public function move($source, $destination, $replace = self::EXISTS_RENAME);
    
    /**
     * Saves a file to the specified destination without invoking file API.
     *
     * This function is identical to file_save_data() except the file will not be
     * saved to the {file_managed} table and none of the file_* hooks will be
     * called.
     *
     * @param string $data
     *   A string containing the contents of the file.
     * @param string $destination
     *   A string containing the destination location. This must be a stream
     *   wrapper URI.
     * @param int $replace
     *   Replace behavior when the destination file already exists:
     *   - FileSystemInterface::EXISTS_REPLACE - Replace the existing file.
     *   - FileSystemInterface::EXISTS_RENAME - Append _{incrementing number}
     *     until the filename is unique.
     *   - FileSystemInterface::EXISTS_ERROR - Do nothing and return FALSE.
     *
     * @return string
     *   A string with the path of the resulting file, or FALSE on error.
     *
     * @throws \Drupal\Core\File\Exception\FileException
     *   Implementation may throw FileException or its subtype on failure.
     *
     * @see \Drupal\file\FileRepositoryInterface::writeData()
     */
    public function saveData($data, $destination, $replace = self::EXISTS_RENAME);
    
    /**
     * Checks that the directory exists and is writable.
     *
     * Directories need to have execute permissions to be considered a directory
     * by FTP servers, etc.
     *
     * @param string $directory
     *   A string reference containing the name of a directory path or URI. A
     *   trailing slash will be trimmed from a path.
     * @param int $options
     *   A bitmask to indicate if the directory should be created if it does
     *   not exist (FileSystemInterface::CREATE_DIRECTORY) or made writable if it
     *   is read-only (FileSystemInterface::MODIFY_PERMISSIONS).
     *
     * @return bool
     *   TRUE if the directory exists (or was created) and is writable. FALSE
     *   otherwise.
     */
    public function prepareDirectory(&$directory, $options = self::MODIFY_PERMISSIONS);
    
    /**
     * Creates a full file path from a directory and filename.
     *
     * If a file with the specified name already exists, an alternative will be
     * used.
     *
     * @param string $basename
     *   The filename.
     * @param string $directory
     *   The directory or parent URI.
     *
     * @return string
     *   File path consisting of $directory and a unique filename based off
     *   of $basename.
     *
     * @throws \Drupal\Core\File\Exception\FileException
     *   Implementation may throw FileException or its subtype on failure.
     */
    public function createFilename($basename, $directory);
    
    /**
     * Determines the destination path for a file.
     *
     * @param string $destination
     *   The desired final URI or filepath.
     * @param int $replace
     *   Replace behavior when the destination file already exists.
     *   - FileSystemInterface::EXISTS_REPLACE - Replace the existing file.
     *   - FileSystemInterface::EXISTS_RENAME - Append _{incrementing number}
     *     until the filename is unique.
     *   - FileSystemInterface::EXISTS_ERROR - Do nothing and return FALSE.
     *
     * @return string|bool
     *   The destination filepath, or FALSE if the file already exists
     *   and FileSystemInterface::EXISTS_ERROR is specified.
     *
     * @throws \Drupal\Core\File\Exception\FileException
     *   Implementation may throw FileException or its subtype on failure.
     */
    public function getDestinationFilename($destination, $replace);
    
    /**
     * Gets the path of the configured temporary directory.
     *
     * If the path is not set, it will fall back to the OS-specific default if
     * set, otherwise a directory under the public files directory. It will then
     * set this as the configured directory.
     *
     * @return string
     *   A string containing the path to the temporary directory.
     */
    public function getTempDirectory();
    
    /**
     * Finds all files that match a given mask in a given directory.
     *
     * Directories and files beginning with a dot are excluded; this prevents
     * hidden files and directories (such as SVN working directories) from being
     * scanned. Use the umask option to skip configuration directories to
     * eliminate the possibility of accidentally exposing configuration
     * information. Also, you can use the base directory, recurse, and min_depth
     * options to improve performance by limiting how much of the filesystem has
     * to be traversed.
     *
     * @param string $dir
     *   The base directory or URI to scan, without trailing slash.
     * @param string $mask
     *   The preg_match() regular expression for files to be included.
     * @param array $options
     *   An associative array of additional options, with the following elements:
     *   - 'nomask': The preg_match() regular expression for files to be excluded.
     *     Defaults to the 'file_scan_ignore_directories' setting.
     *   - 'callback': The callback function to call for each match. There is no
     *     default callback.
     *   - 'recurse': When TRUE, the directory scan will recurse the entire tree
     *     starting at the provided directory. Defaults to TRUE.
     *   - 'key': The key to be used for the returned associative array of files.
     *     Possible values are 'uri', for the file's URI; 'filename', for the
     *     basename of the file; and 'name' for the name of the file without the
     *     extension. Defaults to 'uri'.
     *   - 'min_depth': Minimum depth of directories to return files from.
     *     Defaults to 0.
     *
     * @return array
     *   An associative array (keyed on the chosen key) of objects with 'uri',
     *   'filename', and 'name' properties corresponding to the matched files.
     *
     * @throws \Drupal\Core\File\Exception\NotRegularDirectoryException
     *   If the directory does not exist.
     */
    public function scanDirectory($dir, $mask, array $options = []);

}